There is known a stator winding obtained by inserting a U-shaped conductor through a slot of a stator core, by bending in a circumferential direction a projecting part of the U-shaped conductor that projects out of the stator core, and by joining an end of this projecting part to another U-shaped conductor. By use of a wiring material which is rectangular in cross-section for the U-shaped conductor, an occupying area rate (i.e., occupancy rate of a conductor sectional area to a slot sectional area) of such a stator winding can be increased. For example, in a stator described in JP-A-H11-346448, a U-shaped conductor is bent in a circumferential direction near an opening of a slot of a stator core to arrange its end at a position of joining to another U-shaped conductor.
How to make short an axial length of a part of a stator winding that sticks out of a stator core, i.e., axial length of a coil end is key in downsizing a stator in an axial direction. Accordingly, a bending angle of a U-shaped conductor near an opening of a slot of the stator core needs to be large. However, if the bending angle is too large, the U-shaped conductor is pressed on a slot edge of the stator core, so that a coating film of the U-shaped conductor, and an insulating member provided between the U-shaped conductor and the stator core may be damaged. For this reason, conventionally, the bending angle of the U-shaped conductor cannot be large.
As a measure against this, by increasing thicknesses of the coating film of the U-shaped conductor and the insulating member, the damages to the coating film of the U-shaped conductor and the insulating member by the slot edge of the stator core may be limited with the bending angle made large. Nevertheless, there is a disadvantage of reduction in the occupying area rate when the thicknesses of the coating film of the U-shaped conductor and the insulating member increase.